This research proposes to examine the economic and demographic determinants of household food and nutrient consumption among the poor in the United States. The nutrient composition of the household food basket is a primary determinant of nutritional status. Maintenance of optimal nutritional status is essential in preventative health care. Food availability at the household level is modeled as determined by a two-stage decision making process. At the first stage food expenditure is a function primarily of income and household demographic composition. The second stage of the process is the more important, where quantity of each food is modeled as a function of total food expenditure, each and all food prices, and household demographic composition. A complete demand system framework is proposed to estimate the demand for about 15 aggregated (and exhaustive) food groups simultaneously. Complete demand system estimation is superior to single equation estimation in that the interactive nature of demand for different foods is captured in the model. We further propose to explicitly incorporate household demographic composition in the model. Quantity of foods demanded are transformed into nutrients for inferential purposes. The proposed model is innovative in that it utilizes economic theory to construct a model to derive nutritional inference. The complete demand system model mimics consumer decision making behavior, and thus may provide important insight into potential policy instruments for maintenance of dietary adequacy for the U.S. population.